The present disclosure relates to a switch device including a plurality of differential switches, and more particularly to a layout technology for switch devices.
In recent years, current steering digital-analog (D/A) converters are used for video equipment such as plasma TV sets, Liquid crystal TV sets, organic EL TV sets, and Blu-ray recorders, communication equipment using various communication schemes such as wireless-LAN, power line communication (PLC), and millimeter-wave communication, etc. Such a current steering D/A converter includes a switch device that selectively outputs a plurality of output currents supplied from a plurality of current sources to a pair of output nodes (see U.S. Pat. No. 7,294,892, FIG. 1). This switch device includes a plurality of differential switches each having a pair of differential transistors, the drains of which are electrically connected to the pair of output nodes.
Such a switch device including a plurality of differential switches is also used for other semiconductor integrated circuits such as an HDMI pre-emphasis circuit (e.g., U.S. Pat. No. 7,408,387, FIG. 5) and a slew-rate control circuit.